SOLPART Project Solar reactors for particle processing

SOLPART Project

Solar reactors for particle processing: The solar

rotary kiln

November 28th 2019 - ENSIACET Toulouse

Stefania Tescari, Lamark de Oliveira,

Gkiokchan Moumin

DLR: German aerospace center

Cologne, Germany

SOLPART Project > Infoday > 28.11.2019DLR.de • Chart 1

• The solar rotary kiln concept

• Detailed design

• Construction

• Some trials and errors

• Experiments

• Conclusions and Outlook

Overview


DLR.de • Chart 3 SOLPART Project > Infoday > 28.11.2019

How we introduce concentrated solar energy to the particles?

Solar calcination reactors – Overview


[1] G. Flamant et al., Solar Energy, vol. 24, 1980 [2] A. Imhof, Renewable Energy, vol. 10, 1997 [3] A. Meier et al., Energy, vol. 29, 2004[4] A. Meier et al., Solar Energy, vol. 80, 2006

[1]

[2]

[3]

[4][1]

Indirect concept – Double cylinder

Gas

Particles


crucible

incidentradiation

particlefeeder

particles outlet

thermocouples

Rotary Kiln: Concept



Reactor design

Solar reactor modeling – Thermal model


1

2

3 4 5 6

8 7

Empty reactor

Heat sink on back

Conduction through insulation

Convection and radiation outside

Incident flux Gaussian distribution

Case 1: Improving inner insulation


Conduction losses = 35 %

Tout = 150°C

Improved insulation:


Tout = 120°C

Case 2: Improving axial contact of the ceramic ring



Tout = 150°C

Thermal performances are satisfying

Improved insulation and contact:


Tout = 60°C

Mixing analysis


SOLPART Project > Infoday > 28.11.2019DLR.de • Folie 12

Influence of lifters

Problem:

Image analysis


20 pixels (ca. 280 µm)


Image analysis

0

50000

100000

150000

200000

250000

300000

0 5 10 15 20 25 30 35 40 45

Pix

el w

ith

tra

cer

ne

igh

bo

urs

Image number

Low sensitivity

High sensitivity


S > 0 %

S > 10 %

Optimal lifters shape: 1 mm x 10 mm bars

12 optimal number


Reactor manufacture


Crucible and holding


Housing


Frame


Insulation


d_i 0.25 m

lambda1 0.2 W/mKlambda2 0.035 W/mKthick. 1 0.1 mthick. 2 0.04 m

L 0.7 mA ext 1.17 m²

T_inside 1050 °C

T_end1 666 °CT_out 56 °C

T_amb 20 °C

Reactor design and construction



Screw feeder


Measuring system

Experiments


Test facilities – Solar Furnace


Heliostat ConcentratorExperimental

chamber

• Heliostat dimensions: 8.2 m x 7.4 m (= 57 m²)

• Concentrator dimensions: 7.3 x 6.3 m (= 46 m²)

• Available power in chamber: 25 kW (for DNI of 850 W/m²)


Solar simulator

10 Xenon lamps

Pmax = 24 kW

Pin aperture = 14 kW

Flux density = 4.2 MW/m²

Closed configuration

leaf sealing

gas outlet

sealing

window


First experimental campaign – Solar furnace

1 2

3 4 5 6


Problem: T out too low

Lessons learnt: No insulation gaps allowed


Problem: high temperature at the chain was reached. Fat of chain at high temperature burns


Thermal tests

1 2

3 4 5 6

Experimental campaign-close configuration

> SOLPART Infoday > 27th November 2019DLR.de • Chart 32

→ 𝜂 ≈ 62%𝜂𝑡ℎ =ሶ𝑚 ∙ 𝑐𝑃 ∙ ∆𝑇

𝑄𝑖𝑛𝑐


Chemical tests CRM CaCO3 s ՞CaO s + CO2 g


Second experimental campaign – Solar simulator, CRM

20 slm 45 slm

Problem...

Open configuration (parallel study to solve the window

problem)


incidentradiation

gas outlet

gas outlet

Few more problems with feeding system or

material blocked inside the hopper

But then we could start chemical tests!!


2 3 4 5 6

46 %

𝑋 =𝑋𝑚𝑒𝑎𝑠

𝑋𝑡ℎ𝑒𝑜𝑟

Final results of chemical tests


𝜂𝑇𝑜𝑡 =ሶ𝑚 ∙ 𝑐𝑃 ∙ ∆𝑇 + ሶ𝑚 ∙ 𝑋 ∙ ∆𝐻

𝑄𝑖𝑛𝑐𝑋𝑐ℎ𝑒𝑚 = 𝑋𝑚𝑒𝑎𝑠/𝑋𝑡ℎ𝑒𝑜𝑟

• A continuous solar rotary kiln was built and tested

• 17 succesful chemical tests with rotary kiln

• 4-12 kg/h of CRM treated

• DOC in the range 24-99 %

• Efficiency above 60% were achieved in thermal tests and between 20-

40% in the chemical tests

• Calcination of CaCO3 was successfully shown

Conclusions


Outlook

• The suction unit must be optimized

• Mixing identified as key factor – parallel study

• Window cleaning system is developed

• Scale up


Acknowledgements: EU for financing the Project SOLPART (contract 654663)

under the H2020 research and innovation programme

Thanks for your attention

𝑋𝑐ℎ𝑒𝑚 = 𝑋𝑚𝑒𝑎𝑠/𝑋𝑡ℎ𝑒𝑜𝑟

Efficiency calculations


𝜂𝑇𝑜𝑡 =ሶ𝑚 ∙ 𝑐𝑃 ∙ ∆𝑇 + ሶ𝑚 ∙ 𝑋 ∙ ∆𝐻

𝑄𝑖𝑛𝑐

𝜂𝑐ℎ𝑒𝑚𝜂𝑡ℎ𝑒𝑟𝑚

Experimental campaigns


Many industrial processes treat material in the form of particles

Examples:

-Pharmaceutical industry

-Chemical plants

-Food industry

-Pyrolisis

-Phosphate production

-Cement production ...

Importance of particle treatment


1) Water

2) Concrete

SOLPART Project > Infoday > 28.11.2019

Most used commodities worldwide

DLR.de • Folie 43

[Cement Technology Roadmap 2009, WBCSD and IEA, 2009]

• Main concrete components (Cement + Filler + Water)

• Limestone (CaCO3), Sand (SiO2), Iron ore (Fe2O3), Clay

Cement industry is responsible for 8 % of human-made CO2-emissions

High temperatures necessary in the process:

SOLPART Project > Infoday > 28.11.2019

Facts about cement

DLR.de • Folie 44

[http://www.mastour.com/blog/wp-content/uploads/2013/08/concrete-constituents.jpg][Cement Technology Roadmap 2009, WBCSD and IEA, 2009]

> 900 °C for calcination (CaCO3 CaO + CO2)

> 1300 °C for sintering (Formation of 3 CaO·SiO2)

Conventional cement plant:


Pre-heating Calcination Clinker furnace

Fresh

raw meal Clinker

Heat

recoveryBurner

> 900 °C for calcination (CaCO3 CaO + CO2)

> 1300 °C for sintering (Formation of 3 CaO·SiO2)

Burner

Industrial process


[http://www.wtert.eu/default.asp?Menue=13&ShowDok=49]

The SOLPART project:


Solar

CalcinationStorage

Pre-heating Calcination Clinker furnace

Fresh

raw meal Clinker

Heat

recoveryBurnerBurner



Thanks for your

attention!

http://www.dlr.de/dlr/jobs/en/desktopdefault.a

spx#Promotion/S:77


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SOLPART Project Solar reactors for particle processing